1. Field of the Invention
The present invention relates, in general, to a method and system to be utilized in data processing systems.
2. Description of the Related Art
Data processing systems are systems that manipulate, process, and store data and are notorious within the art. Personal computer systems, and their associated subsystems, constitute well known species of data processing systems.
Personal computer systems typically include a motherboard for mounting at least one microprocessor and other application specific integrated circuits (ASICs), such as memory controllers, input/output (I/O) controllers, and the like. Most motherboards include slots for additional adapter cards to provide additional function to the computer system. Typical functions that a user might add to a computer include additional microprocessors, additional memory, fax/modem capability, sound cards, graphics cards, or the like. The slots included on the motherboard generally include in-line electrical connectors having electrically conductive lands which receive exposed tabs on the adapter cards. The lands are connected to wiring layers, which in turn are connected to a bus that allows the cards to communicate with the microprocessor or other components in the system.
A personal computer system may include many different types of buses to link the various components of the system. Examples of such buses are a "local bus" which connects one or more microprocessors to the main memory, an Industry Standard Architecture (ISA) bus for sound cards and modems, a Universal Serial Bus (USB) for pointing devices, scanners, and digital cameras, a Fire Wire (IEEE-1394) for digital video cameras and high-speed storage drives, and a Peripheral Component Interconnect (PCI) bus for graphics cards, SCSI adapters, sound cards, and other peripheral devices such as isochronous devices, network cards, and printer devices.
Personal computer systems utilize circuit carrying boards housed in the computer's chassis as platforms to secure and interconnect individual electronic components. In order to provide consumer flexibility, these circuit boards are frequently designed to accommodate additional circuit boards, or expansion cards, to provide additional and/or alternative functionality. For example, many personal computer circuit boards are designed with expansion card slots for standard bus interfaces, such as ISA (industry Standard Architecture), EISA (Extended Industry Standard Architecture), and Peripheral Component Interconnect (PCI), into which expansion cards for peripheral devices, such as hard disk controllers, tape controllers, modems and other I/O controllers, may be connected. Many of these expansion cards require connections to devices and equipment external to the computer chassis itself. Accordingly, access points in the computer chassis adjacent to the expansion card connectors are provided to allow for connection between the expansion cards and peripheral devices.
When expansion cards are inserted into expansion card slots, it is important that the expansion cards be held substantially immobile. This is necessary to ensure that appropriate electrical connections are maintained. Those skilled in the art will recognize that if the expansion cards are not held to be substantially immobile, a likelihood exists that the electrical connections of the expansion cards will be interrupted, which can cause errors, malfunctions, and even damage to a data processing system with which the expansion cards are being utilized.
One expectation by modem users when expansion slots are utilized is that various expansion cards can be quickly changed out, or "swapped," when necessary, since it is often necessary to power down a data processing system for a time in order to change out expansion cards. Such down time translates into data processing system unavailability. Thus, while it is important that expansion cards be held substantially immobile within their respective slots, it is also important that any mechanism securing the expansion cards allow for quick and easy release.
Early methods of securing expansion cards recognized the need for immobility, but did not recognize the need for quick-release of the expansion cards. These early methods actually secured the card via a screw which affixed the expansion card to a chassis, or expansion card cage, to which the expansion card slot was affixed. More recent methods have recognized the need for quick release of the expansion cards. These more recent methods utilize plastic clips which provide the necessary quick release functionality.
While the plastic clips provide quick-release functionality, they are notably deficient in holding expansion cards immobile within their slots. With reference now to FIG. 1, depicted is a related art manner of securing an expansion card. Illustrated is that contained within data processing system unit 122 is expansion card latch 100 intended to hold an expansion card, such as expansion card 104, immobile within expansion card chassis 102. When expansion card latch 100 is in its locked position, the expectation is that the face (not shown) of expansion card latch 100 will press upon a tab 108 of expansion card 104 (or expansion card filler panel if expansion card 104 not present) such that expansion card 104 will be held to be substantially immobile.
Those skilled in the art will recognize that the expectation that expansion card 104 will be held immobile is based upon an assumption that expansion card 104 will be of a size such that tab 108 of expansion card 104 will be such that it will be substantially proximate to the face (not shown) of expansion card latch 100 such that expansion card latch 100 may secure expansion card 104 to be substantially immobile. However, those skilled in the art will recognize that size and thicknesses of expansion card tabs vary within the industry, dependent upon manufacturer. In addition, size and thickness of different expansion card tabs also vary from the same manufacturer due to variances in manufacturing. As will be shown, the too-thin tabs will often give rise to substantial slack, or "play," resulting from empty space between the face (not shown) of expansion card latch 100 and tab 108 of expansion card 104, and the too-thick cards will often create an inability for the expansion card latch 100 to lock into place and perform its function.
Referring now to FIG. 2, shown is an expanded isolated view of expansion card latch 100. It can be seen that each expansion card latch 100 rotates about horizontal axis 200 such that face 201 moves down to abut tab 108 of expansion card 104. Depicted is that when release lever 204 clears edge 206 of expansion card latch orifice 208, release lever 204 springs into a position such that expansion card latch 100 cannot move away from the card. This constitutes the "latched" position of expansion card latch 100.
Due to the fact that expansion card latch 100 rotates about horizontal axis 200, those skilled in the art will recognize that card latch 100 is not able to maintain consistent tension between cards with varying thicknesses of mounting brackets. That is, if tab 108 of expansion card 104 is too thin, face 201 will not abut tab 108 with sufficient force to hold expansion card 104 secure in its slot. Conversely, if tab 108 of expansion card 104 is too thick, then release lever 204 will not be able to clear edge 206 of expansion card latch orifice 208, and thus expansion card latch 100 will not be able to lock into a fixed position to secure expansion card 104.
Both the related art problems noted can result in sub-optimal system performance. It has been found empirically that if tab 108 is of less thickness than that appropriate to expansion card latch 100 excessive movement of the card will often result. Those skilled in the art will recognize that such movement can give rise to interruption of the electrical connections of expansion card 104, which can thereby result in sub-optimal data processing system performance. It has also been found empirically that if tab 108 is of greater thickness than that appropriate to expansion card latch 100, the expansion card latch 100 will not be able to lock into a fixed position, which will leave expansion card 104 unsecured, and thus allow expansion card 104 to move freely. Those skilled in the art will recognize that such movement can give rise to interruption of the electrical connections of expansion card 104, which can thereby result in sub-optimal data processing system performance.
Notwithstanding the foregoing, it has been found empirically that expansion card latch 100 is particularly prone to bending and/or breaking when attempt is made to depress release lever 204 and retract expansion card latch 100. That is, it is necessary to depress release lever 204 such that it clears edge 206 and such that face 201 can be retracted up and way from tab 108. Unfortunately, it is common for the human user to mistime the depression of release lever 204 and attempt to retract face 201 without having release lever 204 properly retracted. This often results in the bending or breaking of expansion card latch 100, in that the latch is typically made from relatively brittle plastic which is easily bent and/or broken. This too constitutes a significant problem.
In light of the foregoing, it is apparent that a need exists in the art for a method and system which will secure expansion cards within expansion slots such that the expansion cards are substantially immobile and such that the expansion cards can be quickly released. A need also exists for the method and system to be relatively rugged and not prone to breakage.